//
// DocumentFragment.h
//
// Library: XML
// Package: DOM
// Module:  DOM
//
// Definition of the DOM DocumentFragment class.
//
// Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH.
// and Contributors.
//
// SPDX-License-Identifier:	BSL-1.0
//


#ifndef DOM_DocumentFragment_INCLUDED
#define DOM_DocumentFragment_INCLUDED


#include "Poco/DOM/AbstractContainerNode.h"
#include "Poco/XML/XML.h"
#include "Poco/XML/XMLString.h"


namespace Poco
{
namespace XML
{


    class XML_API DocumentFragment : public AbstractContainerNode
    /// DocumentFragment is a "lightweight" or "minimal" Document object. It is
    /// very common to want to be able to extract a portion of a document's tree
    /// or to create a new fragment of a document. Imagine implementing a user command
    /// like cut or rearranging a document by moving fragments around. It is desirable
    /// to have an object which can hold such fragments and it is quite natural
    /// to use a Node for this purpose. While it is true that a Document object
    /// could fulfill this role, a Document object can potentially be a heavyweight
    /// object, depending on the underlying implementation. What is really needed
    /// for this is a very lightweight object. DocumentFragment is such an object.
    ///
    /// Furthermore, various operations -- such as inserting nodes as children of
    /// another Node -- may take DocumentFragment objects as arguments; this results
    /// in all the child nodes of the DocumentFragment being moved to the child
    /// list of this node.
    ///
    /// The children of a DocumentFragment node are zero or more nodes representing
    /// the tops of any sub-trees defining the structure of the document. DocumentFragment
    /// nodes do not need to be well-formed XML documents (although they do need
    /// to follow the rules imposed upon well-formed XML parsed entities, which
    /// can have multiple top nodes). For example, a DocumentFragment might have
    /// only one child and that child node could be a Text node. Such a structure
    /// model represents neither an HTML document nor a well-formed XML document.
    ///
    /// When a DocumentFragment is inserted into a Document (or indeed any other
    /// Node that may take children) the children of the DocumentFragment and not
    /// the DocumentFragment itself are inserted into the Node. This makes the DocumentFragment
    /// very useful when the user wishes to create nodes that are siblings; the
    /// DocumentFragment acts as the parent of these nodes so that the user can
    /// use the standard methods from the Node interface, such as insertBefore and
    /// appendChild.
    {
    public:
        // Node
        const XMLString & nodeName() const;
        unsigned short nodeType() const;

    protected:
        DocumentFragment(Document * pOwnerDocument);
        DocumentFragment(Document * pOwnerDocument, const DocumentFragment & fragment);
        ~DocumentFragment();

        Node * copyNode(bool deep, Document * pOwnerDocument) const;

    private:
        static const XMLString NODE_NAME;

        friend class Document;
    };


}
} // namespace Poco::XML


#endif // DOM_DocumentFragment_INCLUDED
